标签：
Find the contiguous subarray within an array (containing at least one number) which has the largest sum.
For example, given the array [−2,1,−3,4,−1,2,1,−5,4],
the contiguous subarray [4,−1,2,1] has the largest sum = 6.
More practice:
If you have figured out the O(n) solution, try coding another solution using the divide and conquer approach, which is more subtle.
1 class Solution { 2 public: 3 int maxSubArray(int A[], int n) { 4 5 int sum,maxSum; 6 sum=maxSum=A[0]; 7 for(int i=1;i<n;i++) 8 { 9 if(sum<0) sum=0; 10 sum+=A[i]; 11 12 if(maxSum<sum) maxSum=sum; 13 } 14 return maxSum; 15 } 16 };
1 class Solution { 2 public: 3 int maxSubArray(int A[], int n) { 4 5 divideAndConquer(A,0,n-1); 6 } 7 8 int divideAndConquer(int A[],int left,int right) 9 { 10 11 if(left==right) return A[left]; 12 13 int mid=(left+right)/2; 14 15 16 int leftMax=divideAndConquer(A,left,mid); 17 int rightMax=divideAndConquer(A,mid+1,right); 18 19 int midSum1=0; 20 int midMax1=A[mid]; 21 22 for(int i=mid;i>=left;i--) 23 { 24 midSum1+=A[i]; 25 if(midMax1<midSum1) midMax1=midSum1; 26 } 27 28 int midSum2=0; 29 int midMax2=A[mid+1]; 30 31 for(int i=mid+1;i<=right;i++) 32 { 33 midSum2+=A[i]; 34 if(midMax2<midSum2) midMax2=midSum2; 35 } 36 37 int midMax=midMax1+midMax2; 38 39 return max(max(leftMax,rightMax),midMax); 40 41 42 } 43 };
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原文地址：http://www.cnblogs.com/reachteam/p/4204449.html
